Such an electric lamp is disclosed, for example, in the International Patent Application WO 97/25733. This laid-open application describes an electric incandescent lamp, in particular a motor vehicle headlight lamp, having an incandescent filament enclosed in a vitreous lamp bulb, and a lamp cap consisting of metal parts and plastic parts. The pinch foot, sealed in a gas-tight fashion, of the lamp bulb is fixed in a metal holder part which is, for its part, connected directly or via an intermediate ring to a metal, ringshaped support sleeve. The metal support sleeve is anchored in the plastic cap part, equipped with the electric terminals of the lamp, of the lamp cap. To mount the lamp in the opening, designed as a lampholder, of a reflector, the ring-shaped support sleeve has three reference noses which are arranged in one plane, are distributed equidistantly over the circumference of the support sleeve and engage in the lamp mounting opening of the reflector, and a press-on spring, acting radially outwards, which bears with a clamping fit against the edge of the lamp mounting opening of the reflector. Below the three reference noses, the support sleeve respectively has a point of contact with the edge of the lamp mounting opening of the reflector. One of these points of contact is formed by the press-on spring. The three reference noses are situated on the inner side of the reflector. The sealing of the lamp mounting opening, designed as a lampholder, of the reflector is performed by means of a silicone sealing ring which is arranged between the reflector outer side and the plastic cap part of the lamp cap. This lamp cap, constructed from metal parts and plastic parts, ensures, on the one hand, by means of its metal holder parts for the lamp bulb an exact adjustment of the position of the incandescent filament with respect to the reference plane defined by the three reference noses and, by means of its plastic cap part, adequate sealing of the lamp cap and the reflector against moisture. However, a burr, formed during the production of the reflector, on the outer edge of the lamp mounting opening of the reflector has an unfavorable influence on the mounting position of the lamp, and causes an undesired maladjustment of the incandescent filament with respect to the optical axis of the reflector.